Q23 - When people experience throbbing

[agersh144]

I got this one wrong I didn't have time to diagram so MLSAT mods please check out my post-test work to make sure it's all OK.

Here's my diagrams:

TT or TG > DP
DP > TD or GD
___________________

/TT and /TG > /TD & /GD

TT = Throbbing Tooth
TG = Throbbing Gums
DP = Dental Problem
TD = Tooth Decay
GD = Gum Disease

Abstract Form:
Basically A or B > C
C > D or E
___________
/A and /B > /D and /E

This argument is strange. Negating both elements of the sufficient condition and then negating the 4th and 5th variables of the necessary end of the chain. In other words mistaken/illegal negation to both sides.

Answer Choice A:
C > JN
NN & S > /JD
___________
(MS) C > /NN & /S

Not only does this not match but there's an additional error in that the arguement equivocates between people who drink a lot of coffee and medical students who drink a lot of coffee.

Answer Choice B:
LPP > MD & PT
/PT
________
PP > /L

This is just way off.

Answer Choice C:
SNC > SI or A
____________
/SI > /SNC

Nope, not a match.


Answer Choice D:
P or C > CCM
_______________
/P and /C > /CCM

Bingo. Negation to both sides. This is an illegal/mistaken negation.

P = Physics
C = Chemistry
CCM = Consider Career in Medicine

Answer Choice E)
OPH or OPT > /LTDD
____________
/LTDD > OPH or OPT

[maryadkins]

Well done, and looks great!

One tip for situations like this where you don't have time to break down the argument during the test is that if the argument in the stimulus is flawed and the argument in an answer choice appears not to be (like (B) in this case), it's not going to be the answer.

It's an obvious point--but it can be easily forgotten during abstract thinking about conditional logic under pressure!

[WaltGrace1983]

Answer Choice A:
C > JN
NN & S > /JD
___________
(MS) C > /NN & /S

Not only does this not match but there's an additional error in that the arguement equivocates between people who drink a lot of coffee and medical students who drink a lot of coffee.

I might be wrong, but I actually don't think this is a flaw. This argument works on the premise that ALL people who drink a lot of coffee (are said to) have jittery nerves. Medical students would be included in that "all" people.

Coffee → Jittery nerves
Jittery nerves → ~(Neonatology or Surgery)
Medical Students = coffee
⊢
Medical students = ~(Neonatology or Surgery)

The argument would be different if it said "MEDICAL STUDENTS who drink a lot of coffee are said to have jittery nerves. Therefore, ALL students who drink a lot of coffee should not become..."

This hypothetical argument is flawed because it increases the scope of the argument (from medical students) to a group not previously discussed (all students). Going the other way by making a generalization about ALL people and then talking about medical students specifically wouldn't be flawed in this case I believe.

Just for completeness sake...

(A) doesn't appear to be flawed

(B) is not flawed at all because it denies the necessary condition to arrive at denying the sufficient condition (otherwise known as utilizing the contrapositive)

(C) falsely assumes ~(allergy). It could very well be that Barton - while not having a sinus infection - has an allergy. The argument never says this is not the case though. This argument could only follow if it said "Therefore, if Barton does not have a sinus infection AND does not have an allergy..."

(D) Correct. False negation, just like the original argument.

(E) has the wrong flaw by falsely equating having "specialized training" to "accurately diagnosing." I could accurately diagnose cancer by mere chance but that doesn't mean I have "specialized training."